The present invention relates to a gun bolt locking mechanism. More particularly, the present invention relates to a device and method for locking a bolt to a bolt carrier during certain stages of the cycle of operation of a self-loading gun. It finds particular utility in a fully automatic gun and especially in a rotary, multi-barreled, machine gun.
The operation of self-loading, single-barreled guns is well known. Whether in semi-automatic or full automatic operation, the rate of fire is limited by the speed at which the gun can load, fire, and eject the spent cartridge of the ammunition being fired. Most of such weapons use the energy associated with the expanding gas or resulting recoil to operate the gun. Rotary machine guns are weapons that are designed to fire ammunition at an extremely high rate when compared to other types of weapons. A rotary machine gun includes a series of barrels that are mounted on a rotor assembly. The rotor assembly is externally driven, that is, power is applied to the rotor to rotate it with respect to a stationary gun housing to load, fire, and eject the spent casing as ammunition is fired in each barrel in rapid succession. As ammunition is fired in one barrel, a round is being loaded into another barrel, while a spent casing is extracted from yet another barrel. In this manner, the rotary machine gun achieves the high rate of fire.
Each round of ammunition is fired by igniting a primer contained within the cartridge case. There are two commonly used methods of igniting the primer. Some guns use electrical energy to ignite the primer, while other guns use mechanical force applied to the primer, normally by a firing pin. Accordingly, there are also two types of ammunition: electrically primed and percussion primed. Electrically primed ammunition must be fired with electrical energy and percussion primed ammunition must be fired with a mechanical impact.
Certain rotary machine guns manufactured by General Dynamics Armament and Technical Products are commonly used as part of the weapons systems on fighter aircraft. It has been discovered that under certain conditions, radiation generated by radar and communications equipment can ignite electrically primed ammunition. When these conditions occur, the uncontrolled ignition of the 20-mm shells creates a serious safety hazard. To eliminate this safety hazard, the aircraft should be able to switch from electrically-primed ammunition to percussion-primed ammunition with little or no modification to the gun.
In certain rotary machine guns having a reciprocating bolt associated with a reciprocating bolt carrier, a means is required to lock the gun bolt in an extended position relative to the bolt carrier during most of the gun cycle (cartridge extract, eject, rear dwell, cartridge feed, and cartridge ram), and to release the extended bolt during the rest of the gun cycle (bolt locking, firing, and unlocking).
With a rotary machine gun that only fires electrically-primed ammunition, the bolt locking mechanism can pass directly through the bolt body. For a firing mechanism that will work with both electric- and percussion-primed ammunition, however, the bolt locking mechanism cannot pass through the bolt body due to the need for a centrally-located firing pin and its spring mechanism.